An aneurysm is a ballooning of the wall of an artery resulting from the weakening of the artery due to disease or other conditions. Left untreated, the aneurysm will frequently rupture, resulting in loss of blood through the rupture and death.
Aortic aneurysms are the most frequent form of arterial aneurysm and are life threatening. The aorta is the main artery, which supplies blood to the circulatory system. The aorta arises from the left ventricle of the heart, passes upward and bends over behind the heart, and passes down through the thorax and abdomen. Among other arterial vessels branching off the aorta along its path, the abdominal aorta supplies two side vessels to the kidneys, the renal arteries. Below the level of the renal arteries, the abdominal aorta continues to about the level of the fourth lumbar vertebrae (or the navel), where it divides into the iliac arteries. The iliac arteries, in turn, supply blood to the lower extremities and perineal region.
It is common for an aortic aneurysm to occur in that portion of the abdominal aorta between the renal arteries and the iliac arteries. This portion of aortic aneurysm larger than about 5 cm in diameter in this section of the aorta is ominous. Left untreated, the aneurysm may rupture, resulting in rapid, and usually fatal, hemorrhaging. Typically, a surgical procedure is not performed on aneurysms smaller than 5 cm because presently no statistical benefit exists in performing such procedures.
Aneurysms in the abdominal aorta are associated with a particularly high mortality rate; accordingly, current medical standards call for urgent operative repair. Abdominal surgery, however, results in substantial stress to the body. Although the mortality rate for an aortic aneurysm is extremely high, there is also considerable mortality and morbidity associated with open surgical intervention to repair an aortic aneurysm. This intervention involves penetrating the abdominal wall to the location of the aneurysm to reinforce or replace the diseased section of the aortic aneurysm. A prosthetic device, typically a synthetic tube graft, is used for this purpose. The graft serves to exclude the aneurysm from the circulatory system, thus relieving pressure and stress on the weakened section of the aorta at the aneurysm.
Repair of an aortic aneurysm by surgical means is a major operative procedure. Substantial morbidity accompanies the procedure, resulting in a protracted recovery period. Further, the procedure entails a substantial risk of mortality. While surgical intervention may be indicated and the surgery carries attendant risk, certain patients may not be able to tolerate the stress of intra-abdominal surgery. It is, therefore, desirable to reduce the mortality and morbidity associated with intra-abdominal surgical intervention.
In recent years, apparatus and method development have attempted to treat an aortic aneurysm without the attendant risks of intra-abdominal surgical intervention. Among them are inventions disclosed and claimed in Kornberg, U.S. Pat. No. 4,562,596 for Aortic Graft, Device and Method for Performing an Intraluminal Abdominal Aortic Aneurysm Repair; Lazarus, U.S. Pat. No. 4,787,899 for Intraluminal Graft Device, System and Method; and Taheri, U.S. Pat. No. 5,042,707 for Intravascular Stapler, and Method of Operating Same.
Kornberg discloses an aortic graft comprising a flexible tubular material having a plurality of struts to lend the graft stability and resiliency. The struts have angled hooks with barbs at their upper ends which are securely attached to the inside of the aorta above the aneurysm. Kornberg's graft is inserted using a tubular device also disclosed in his patent. Kornberg, however, only anchors the proximal end of the graft. Kornberg claims that the downward flow of blood holds the distal graft securely in place, so that no mechanical attachment is necessary distally. The blood pressure in the abdominal aorta, however, is typically in the magnitude of 130 mm of mercury (Hg). In spite of the direction of flow of blood through the graft, proximal to distal, substantial back pressure within the aneurysm will result unless the distal end is also mechanically attached to the aorta in a manner that prevents substantial leakage of blood between the graft and the aorta. Without distal attachment, the device of Kornberg will not effectively exclude the weakened arterial wall at the site of the aneurysm from the forces and stress associated with the blood pressure.
Lazarus discloses a grafting system that employs a plurality of staples mounted in the proximal end of the graft. Lazarus's staples are forced through the aorta wall by means of a balloon catheter. As does Kornberg, Lazarus discloses staples mounted only in the proximal end of the graft. There is no teaching or suggestion in Lazarus, U.S. Pat. No. 4,787,899 as to the desirability of, let alone means for, mechanically attaching the graft to the distal aorta below the level of the aneurysm.
Taheri discloses an articulatable stapler for implanting a graft in a blood vessel. The stapler is in the form of an elongated catheter with a plurality of segments mounted on the distal end of the catheter. The segments have beveled faces and are connected to each other by hinges. A stylet runs through the catheter to the most distal segment. The most distal segment is moved, in conjunction with the other segments, into a firing position that is substantially perpendicular to the main catheter body by the action of pulling on the stylet. The staple is implanted by using two other stylets, which act as fingers to bend the staple into its attachment position.
Taheri, however, appears to be a single-fire design which can only implant one staple at a time. After each stapler is implanted, Taheri's design apparently requires that the catheter be removed before another staple is loaded. In addition, Taheri's does not teach or suggest an appropriate density of staples to secure a graft against the pulsatile blood flow of the aorta. Pressures within the aorta range from 120 mm Hg pressure to 200 mm Hg pressure. Without adequate attachment, the graft may leak around the edges continuing to allow life threatening pressures to develop in the aneurysm, and may not even remain in place.
During a surgical procedure a suture normally may be used to attach a surgical component to a vessel. Alternatively, an innovative fastener disclosed in U.S. Pat. Nos. 5,957,940 and 5,997,556 reveal a fastener assembly having a flexible fastening means under a compressive force. The fastener comprises a spring assembly of coils having a first portion adapted to be positioned on one side of the surgical component and the vessel wall, a second portion adapted to be positioned on another side of the surgical component and the vessel wall, and an intermediate portion connecting the first portion and the second portion, the intermediate portion extending through the vessel wall and the surgical component. Although the innovative fastener is directed to a new and improved method of repairing an abdominal aortic aneurysm, a problem persists as to removing this particular fastener when misplacement occurs. Additionally, it would be beneficial to decrease any damage to the surrounding vessel wall and surgical component without discomforting the surgical patient.
What is needed, therefore, is an extractor that accommodates the recently inserted innovative fasteners that may have been misplaced or otherwise require removal. Specifically, the extractor should be used to manipulate the innovative fastener so that the surgical procedure can continue as planned rather than having to discontinue the procedure and convert the procedure into an open operation for removal of the fasteners.
It is therefore an advantage of some, but not necessarily all, embodiments of the present invention to provide a fastener remover for removing an inserted surgical fastener during a surgical procedure.
It is another advantage of embodiments of the present invention to provide a fastener remover for removing a surgical fastener when misplacement occurs.
It is another advantage of embodiments of the present invention to provide a fastener remover that decreases damage to the surrounding vessel wall and surgical component during removal.
It is yet another advantage of embodiments of the present invention to provide a fastener remover that allows for fastener removal during a surgical procedure without the need for converting the procedure into an open operation.
Additional advantages of various embodiments of the invention are set forth, in part, in the description that follows and, in part, will be apparent to one of ordinary skill in the art from the description and/or from the practice of the invention.